As far as tax monitoring goes, I'm not sure that account and transaction monitoring is helpful. If you have a stated income near the median, yet own a palace,

As far as tax monitoring goes, I'm not sure that account and transaction monitoring is helpful. If you have a stated income near the median, yet own a palace, a Porsche and a Lamborghini for the wife, a yacht &c something just has to be off. Apparently you can see the phenomenon in at work in Greece. If you have undeclared income, at some point the funds have to enter the regular economy, and from then on it's just old-fashioned police work. Just how you do the actual enforcement, that's a different issue, especially if corruption is entrenched already.